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    <meta charset="UTF-8">
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    <title>Document</title>
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<body>
    <div id = "box">

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    <script>
        //定义常量a，常量不能修改
        const a = 10 ; 
        //报错
        //a= 20 ; 
        console.log(a);

        //在js中大多数的变量都要采用const声明。因为有些东西是不会变的。
        const divObject = document.querySelector("#box");
        console.log(divObject);



        
    </script>
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